/*
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 *    StreamTokenizerUtils.java
 *    Copyright (C) 2000-2012 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.core.converters;

import java.io.IOException;
import java.io.Serializable;
import java.io.StreamTokenizer;

/**
 * Helper class for using stream tokenizers
 * 
 * @author Mark Hall (mhall{[at]}pentaho{[dot]}com)
 * @version $Revision$
 */
public class StreamTokenizerUtils implements Serializable {

    /** For serialization */
    private static final long serialVersionUID = -5786996944597404253L;

    /**
     * Gets token, skipping empty lines.
     * 
     * @param tokenizer the stream tokenizer
     * @throws IOException if reading the next token fails
     */
    public static void getFirstToken(StreamTokenizer tokenizer) throws IOException {

        while (tokenizer.nextToken() == StreamTokenizer.TT_EOL) {
        }
        ;
        if ((tokenizer.ttype == '\'') || (tokenizer.ttype == '"')) {
            tokenizer.ttype = StreamTokenizer.TT_WORD;
        } else if ((tokenizer.ttype == StreamTokenizer.TT_WORD) && (tokenizer.sval.equals("?"))) {
            tokenizer.ttype = '?';
        }
    }

    /**
     * Gets token.
     * 
     * @param tokenizer the stream tokenizer
     * @throws IOException if reading the next token fails
     */
    public static void getToken(StreamTokenizer tokenizer) throws IOException {

        tokenizer.nextToken();
        if (tokenizer.ttype == StreamTokenizer.TT_EOL) {
            return;
        }

        if ((tokenizer.ttype == '\'') || (tokenizer.ttype == '"')) {
            tokenizer.ttype = StreamTokenizer.TT_WORD;
        } else if ((tokenizer.ttype == StreamTokenizer.TT_WORD) && (tokenizer.sval.equals("?"))) {
            tokenizer.ttype = '?';
        }
    }

    /**
     * Throws error message with line number and last token read.
     * 
     * @param theMsg    the error message to be thrown
     * @param tokenizer the stream tokenizer
     * @throws IOException containing the error message
     */
    public static void errms(StreamTokenizer tokenizer, String theMsg) throws IOException {

        throw new IOException(theMsg + ", read " + tokenizer.toString());
    }
}
